460 Big-Block Build Part 2 - Large and In Charge

Hot heads and a hot cam make for a high-horsepower recipe

Richard Holdener

May 17, 2011

Back in Part 1 of Large and In Charge, we subjected our wrecking yard 460 Ford to a few mild modifications. Rather than go hog wild, we installed the upgrades one at a time to illustrate the gains offered by each. Some of the performance products netted impressive results, some less than expected. This is why we often go to the trouble of testing, as you never know what the combination will respond to.

In Part 1, we improved the power output of our boneyard Blue Oval 460 from 349 hp and 492 lb-ft of torque to 437 hp and 507 lb-ft of torque. This was accomplished by improving the heads, cam, and induction, though it should be stressed that every effort was made to keep the combination mild and streetable. With more than 500 lb-ft of torque, this was one seriously torquey motor, but the 437 hp would make an impressive street performer as well. Toss in the near-stock idle quality and you have the makings of one heck of a daily driver. The problem is that for many, 437 hp just isn’t quite enough, especially from a big-block. That is why we stepped things up in Part 2 and took our 460 from mild to wild.

Making big power with a big motor isn’t terribly difficult. All you have to do is concentrate on getting air into and out of the motor. This means you should concentrate on the heads, cam, and induction system, just as we did in Part 1. The difference between the build up in Part 1 and this adventure in Part 2 is simply a matter of degrees. Where our focus was on a mild street application in Part 1, we stepped things up in Part 2 to include motivation for a serious street/strip machine.

The success of any buildup is often a function of setting specific goals. One such goal is a well-defined power output. If you only need 400 hp to meet your performance criteria, there is no need to build something that makes 1,000 hp. Within that power goal are variables like driveability, or more accurately how much driveability are you willing to sacrifice in your quest for power? In most cases, power output and driveability are mutually exclusive or, at the very least, at odds with one another. Cam timing is a major contributor to driveability, followed by the induction system and, to a lesser extent, cylinder head configuration. It all comes down to where in the rev range you’re looking to maximize power production.

For this buildup, we decided on a realistic power goal of 600 hp. A nice round number to be sure, but even more impressive given the fact that we elected to stick with the production iron cylinder heads. Sure, aluminum heads are plentiful for the big-block Fords (something we’ll take full advantage of in Part 3), but we decided that we would reach said 600hp goal by porting the stock heads.

To that end, we shipped them out to the 460 Ford experts at MPG heads, in Englewood, Colorado. Having successfully raced Fords (including stock-headed versions) for the last 30 years or so, MPG was eminently qualified to port our ’68 castings.

Once MPG had worked its CNC magic, the head flow jumped to nearly 340 cfm on the intake. We also took advantage of MPG’s offer to run a set of its exhaust port plates. According to MPG, the port plates greatly improved the flow rate of the notoriously weak exhaust ports past 0.400-inch lift. Where the flow rate of the stock ports stagnated around 0.400 lift, the airflow continued to climb past 0.600 lift with the port plates. The heads were also treated to Cobra Jet-sized valves (2.25/1.75), a performance valve job and a valvespring upgrade (135/335 pounds) designed to work with the flat-tappet cam supplied by Cam Research.